At the same time, readers who want to keep up with best-selling novels or current nonfiction, or who want to build a collection of classics, have various clubs to choose from. Buyers of paperbacks and small press publications can also find clubs devoted to their needs.

For 56 years now, America's book clubs have served readers who prefer not to shop in stores, often because of the distance involved, higher prices, more limited selection, sales pressure, or lack of guidance. Latest figures from the Association of American Publishers indicate book clubs had net sales of $538.3 million in 1980, while publishers sold $695.9 million worth of adult trade hardcovers that year.

Though their origins might be traced to the subscription library founded by Benjamin Franklin in 1731, or the ''tract-of-the-month'' plan inaugurated by the American Tract Society in 1825, or the clubs that sprang up in Germany after World War I, the first American company to offer regular selections by mail at the reader's option was Book-of-the-Month Club (BOMC), founded in 1926 by Harry Scherman.

Scherman, a veteran of various by-mail marketing and advertising enterprises, hit on an original idea: a panel of distinguised literary judges, free to choose monthly selections using their taste rather than business considerations as the sole criterion.

Scherman's sincerity got an immediate test, when the first panel selected an amorphous novel entitled ''Lolly Willowes.'' It was sent to the club's 4,750 members and ''came back in droves,'' Scherman later recalled, leaving him to wonder if he'd made a colossal mistake. The current BOMC editor-in-chief, Gloria Norris, says, however, that the vast majority of the judges' choices over the years have vindicated Scherman's plan and that the soundness of the selection process, not duplicated by any other club, has been a key to BOMC's longevity.

Shortly after Scherman founded his club, a number of others appeared, but many of them folded during the depression. Scherman's hardiest competitor was the Literary Guild of America, incorporated in 1922 but not actually activated until a couple of months after Book-of-the-Month Club got off the ground. Doubleday acquired a minor interest in the Literary Guild in 1928 and complete control in 1934, and the publisher operates the Guild today, along with a score of more specialized company clubs.

From the '30s through the '60s various clubs came and went, as tastes and marketing strategies waxed and waned. The last 10 years have seen the rise of most of the specialty clubs active today, in a total field of well over 100.

Publishers and booksellers reacted with suspicion and hostility to the early clubs' price-cutting tactics, but today publishers feel selection of their books for a major club's list actually boosts sales in stores by providing an independent vote of confidence, often cited in ads or on book jackets.

Since the late '40s the clubs have been legally obliged to print their own editions rather than buy copies from the publishers.

America's newest club is the Library of America. Being launched this month with funding from the National Endowment for the Humanities and the Ford Foundation, it will focus on classic American writers, such as Melville, Hawthorne, and Twain (see details in listing below).

How do the clubs operate? The vast majority depend on ''negative option,'' which means that they announce their main selections in regular bulletins, and, unless a member responds by a specific date requesting another book or no book at all, he or she receives the main selection automatically. Most of the clubs also require a minimum purchase. Some, like Book-of-the-Month and History Book Club, offer editions of the same quality as the publishers. Others, such as Literary Guild, sometimes print smaller books, or use cheaper paper or less stringent production specifications than the publishers, so as to offer members a better price.

Some publishers, like Doubleday, own a number of clubs. McGraw-Hill, for instance, has nearly two dozen offering books for professional people. Macmillan has nearly 20 clubs. In 1977, Book-of-the-Month Club was purchased by Time, Inc., which now runs it along with its five siblings - Fortune Book Club, Book-of-the-Month/Science, Cooking and Crafts, Dolphin, and Quality Paperback Book Club.

Some of the clubs are small and independent, however. The Cat Lovers Book Club, for instance, launched earlier this year, is a modest operation run by Edward J. Hackney, a young entrepreneur who started his first club 21/2 years ago. He sank $100,000 into that earlier venture and notes that high postal costs and interest rates make it difficult for newcomers to survive.

What should a potential member look at when considering a club? There's the selection process - sometimes explained in detail but often not explained in ads and brochures. One might also consider the amount of discount, minimum purchase requirements, number of books offered, whether club editions are comparable to publishers' editions, and whether a club offers books from all publishers or primarily from its parent company.